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Fine-Grained Non-Interactive Key-Exchange without Idealized Assumptions

Authors:
Yuyu Wang , University of Electronic Science and Technology of China
Chuanjie Su , University of Electronic Science and Technology of China
Jiaxin Pan , University of Kassel, Germany
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DOI: 10.1007/978-3-031-68379-4_8 (login may be required)
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Presentation: Slides
Conference: CRYPTO 2024
Abstract: In this paper, we study multi-party non-interactive key ex-change (NIKE) in the fine-grained setting. More precisely, we propose three multi-party NIKE schemes in three computation models, namely, the bounded parallel-time, bounded time, and bounded storage models. Their security is based on a very mild assumption (e.g. NC1 \subsetneq \oplus L/poly) or even without any complexity assumption. This improves the recent work of Afshar, Couteau, Mahmoody, and Sadeghi (EUROCRYPT 2023) that requires idealized assumptions, such as random oracles or generic groups. Additionally, we show that all our constructions satisfy a natural desirable property that we refer to as extendability, and we give generic transformations from extendable multi-party NIKE to multi-party identity-based NIKEs in the fine-grained settings.
BibTeX
@inproceedings{crypto-2024-34314,
  title={Fine-Grained Non-Interactive Key-Exchange without Idealized Assumptions},
  publisher={Springer-Verlag},
  doi={10.1007/978-3-031-68379-4_8},
  author={Yuyu Wang and Chuanjie Su and Jiaxin Pan},
  year=2024
}